In a post on his website, Quinto wrote that he was motivated after learning of the death of Jamey Rodemeyer, the gay teen who committed suicide last month after years of being bullied. Quinto last year shot an emotional video for “It Gets Better,” a campaign aimed at ending the antigay bullying that has led many gay teens to suicide.

"When I found out that Jamey Rodemeyer killed himself, I felt deeply troubled," he wrote. "But when I found out that Jamey Rodemeyer had made an 'It Gets Better' video only months before taking his own life, I felt indescribable despair. "

He said he then felt the need to publicly acknowledge his homosexuality in the hope that he could help prevent something similar from happening again.

“In light of Jamey's death," he wrote, "it became clear to me in an instant that living a gay life without publicly acknowledging it is simply not enough to make any significant contribution to the immense work that lies ahead on the road to complete equality."

He continued: "Our society needs to recognize the unstoppable momentum toward unequivocal civil equality for every gay, lesbian, bisexual and transgendered citizen of this country. Gay kids need to stop killing themselves because they are made to feel worthless by cruel and relentless bullying."

He also encouraged parents to teach their children "the principles of respect and acceptance."

"I believe in the power of intention to change the landscape of our society, and it is my intention to live an authentic life of compassion and integrity and action," he continued. "Jamey Rodemeyer's life changed mine. And while his death only makes me wish that I had done this sooner, I am eternally grateful to him for being the catalyst for change within me. Now I can only hope to serve as the same catalyst for even one other person in this world."

While Quinto's sexuality has been questioned and picked at in the tabloids over the years, the actor has never publicly addressed the rumors. He has, however, played many gay roles (on Tori Spelling’s So NoTORIous and on the new FX series American Horror Story) and been an outspoken advocate of equal rights.

Quinto told New York magazine that his role last year in the off-Broadway revival of Angels in America -- in which he played a gay man who abandons his AIDS-stricken boyfriend -- was both “the most challenging thing I’ve ever done as an actor and the most rewarding.”

“At the same time,” he added, “as a gay man, it made me feel like there’s still so much work to be done, and there’s still so many things that need to be looked at and addressed.”

He also argued that the recent positive changes for the gay community (the legalization of gay marriage in New York) are qualified by the backwards steps of continued gay bullying and Rodemeyer's suicide.

“Again, as a gay man I look at that and say there’s a hopelessness that surrounds it, but as a human being I look at it and say ‘Why? Where’s this disparity coming from, and why can’t we as a culture and society dig deeper to examine that?’ We’re terrified of facing ourselves.”

Quinto is currently in theaters in a small role in What’s Your Number? -- playing a boyfriend of Anna Faris -- and will be seen later this month playing a gay dead owner of the haunted house in American Horror Story. His new movie, Margin Call, which he co-produced and stars opposite Kevin Spacey, Paul Bettany and Jeremy Irons, opens Oct. 21.